KR20240097937A - Perfluoroelastomer composition and perfluoroelastomer cross-linked product - Google Patents

Abstract

At least one compound (C) selected from the group consisting of a nitrile group-containing perfluoroelastomer (A), an iodine- or bromine-containing perfluoroelastomer (B) that does not contain a nitrile group, and an inorganic nitride and ammonia-generating compound. Provided is a perfluoroelastomer composition containing

Description

Perfluoroelastomer composition and perfluoroelastomer cross-linked product

The present disclosure relates to perfluoroelastomer compositions and perfluoroelastomer crosslinks.

Patent Document 1 discloses a perfluoropolymer having randomly copolymerized units of tetrafluoroethylene, perfluoro(alkylvinyl)ether, and nitrile group-containing fluorinated curing site monomer, and this perfluoropolymer also has this Perfluoropolymers are described comprising iodine moieties present in an amount of at least about 0.05% by weight of the perfluoropolymer.

Patent Document 2 discloses a curable composition consisting of a perfluoroelastomer and a curing agent, wherein the perfluoroelastomer is (1) tetrafluoroethylene, (2) perfluoro(alkylvinyl)ether, and perfluoro(alkoxyvinyl). ) ether, and mixtures thereof; A curable composition selected from the group consisting of compounds other than , diaminobisphenol AF, organic peroxides, and ammonium salts of organic or inorganic acids that decompose at a temperature of 40° C. to 330° C. to generate ammonia is described.

Japanese Patent Publication No. 05-500070 Japanese Patent Publication No. 2004-532902

The present disclosure aims to provide a perfluoroelastomer composition capable of obtaining a cross-linked product with excellent compression set properties and excellent transparency, and a perfluoroelastomer cross-linked product with excellent compression set properties and excellent transparency. .

According to the present disclosure, at least one selected from the group consisting of a nitrile group-containing perfluoroelastomer (A), an iodine- or bromine-containing perfluoroelastomer (B) that does not contain a nitrile group, and an inorganic nitride and an ammonia-generating compound. A perfluoroelastomer composition containing compound (C) is provided.

In the perfluoroelastomer composition of the present disclosure, the content of the iodine or bromine-containing perfluoroelastomer (B) is preferably 0.5 to 10 parts by mass based on 100 parts by mass of the nitrile group-containing perfluoroelastomer (A). .

In the perfluoroelastomer composition of the present disclosure, it is preferred that compound (C) is silicon nitride.

Additionally, according to the present disclosure, a perfluoroelastomer crosslinked product obtained by crosslinking the above perfluoroelastomer composition is provided.

Additionally, according to the present disclosure, a perfluoroelastomer crosslinked product having a haze value of 95% or less and a compression set of 25 to 40% is provided.

The crosslinked perfluoroelastomer of the present disclosure preferably has a total light transmittance of 85% or more.

The crosslinked perfluoroelastomer of the present disclosure preferably contains a triazine ring.

The crosslinked perfluoroelastomer of the present disclosure preferably contains an iodine atom or a bromine atom.

The crosslinked perfluoroelastomer of the present disclosure preferably contains silicon atoms.

According to the present disclosure, it is possible to provide a perfluoroelastomer composition capable of obtaining a cross-linked product having excellent compression set properties and excellent transparency, and a perfluoroelastomer cross-linked product having excellent compression set properties and excellent transparency.

Hereinafter, specific embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

The perfluoroelastomer composition of the present disclosure is selected from the group consisting of a nitrile group-containing perfluoroelastomer (A), an iodine- or bromine-containing perfluoroelastomer (B) that does not contain a nitrile group, and an inorganic nitride and ammonia-generating compound. It contains at least one compound (C) that is

In Patent Document 1, the above-mentioned perfluoropolymer reacts with a peroxide curing agent and a cross-linking auxiliary to form a unique polymer network structure (here, cross-linking occurs at random points along the polymer chain and both ends of the chain). ) is described as occurring. Additionally, it is described that this perfluoropolymer has excellent strength, compression set properties, and good processing properties.

However, when the perfluoropolymer described in Patent Document 1 is crosslinked using a peroxide curing agent and a crosslinking aid, there is a problem in that excellent compression set properties cannot be obtained.

Patent Document 2 describes that it is advantageous to have a perfluoroelastomer article that is translucent or transparent, light-colored, or colorless, and contains a very low amount of metal, while maintaining good tensile properties and low compression set. It is done. However, the cross-linked product obtained from the curable composition described in Patent Document 2 also has the problem of not being able to sufficiently achieve both compression set properties and transparency.

As a result of careful examination of means for solving these problems, it was found that by adding an iodine- or bromine-containing perfluoroelastomer (B) and a compound (C) that do not contain a nitrile group to the nitrile group-containing perfluoroelastomer (A), It was found that the transparency of the resulting cross-linked product could be improved without significantly deteriorating the compression set characteristics of the cross-linked product. The reason for this is not clear, but due to the action of compound (C), the nitrile group-containing perfluoroelastomer (A) forms a crosslinked perfluoroelastomer, while the iodine- or bromine-containing perfluoroelastomer (B) forms a crosslinked perfluoroelastomer. It is presumed that this is because it can move freely in the cross-linked product and can compensate for some defects that cause clouding of the cross-linked product. The perfluoroelastomer composition of the present disclosure and the crosslinked perfluoroelastomer of the present disclosure were completed based on this knowledge.

The perfluoroelastomer composition of the present disclosure contains at least perfluoroelastomers (A) and (B) as perfluoroelastomers. In the present disclosure, the perfluoroelastomer is a fluoropolymer in which the content of perfluoro monomer units relative to all polymerized units is 90 mol% or more, preferably 91 mol% or more, and has a glass transition temperature of 20° C. or less. , It is a fluoropolymer having a melting peak (ΔH) size of 4.5 J/g or less, and the concentration of fluorine atoms contained in the fluoropolymer is 71% by mass or more, preferably 71.5% by mass or more. In the present disclosure, the concentration of fluorine atoms contained in the fluoropolymer is calculated by calculating the concentration (% by mass) of fluorine atoms contained in the fluoropolymer from the type and content of each monomer constituting the fluoropolymer. will be.

In the present disclosure, a perfluoro monomer is a monomer that does not contain a carbon atom-hydrogen atom bond in the molecule. The perfluoro monomer may be a monomer in which, in addition to the carbon atom and the fluorine atom, some of the fluorine atoms bonded to the carbon atom are substituted with chlorine atoms, and in addition to the carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, and a boron atom. It may have an atom or a silicon atom. The perfluoro monomer is preferably a monomer in which all hydrogen atoms are replaced with fluorine atoms. The perfluoro monomer does not include a monomer that provides a crosslinking site.

The monomer that provides a crosslinking site is a monomer (cure site monomer) having a crosslinkable group that provides a crosslinking site for forming a crosslink to the perfluoroelastomer.

In the present disclosure, the content of each monomer constituting the perfluoroelastomer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, fluorescence X-ray analysis, and other known methods depending on the type of monomer.

As the perfluoro monomer that gives the perfluoro monomer unit constituting the perfluoroelastomer,

Tetrafluoroethylene [TFE],

Hexafluoropropylene [HFP],

General formula (13): CF ₂ =CF-ORf ¹³

A fluoro monomer represented by (wherein Rf ¹³ represents a perfluoroalkyl group having 1 to 8 carbon atoms),

General formula (14): CF ₂ =CFOCF ₂ ORf ¹⁴

(Wherein, Rf ¹⁴ is a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, a cyclic perfluoroalkyl group having 5 to 6 carbon atoms, a linear or branched fluoroalkyl group having 2 to 6 carbon atoms containing 1 to 3 oxygen atoms, A fluoro monomer represented by a branched perfluoroxyalkyl group, and

General formula (15): CF ₂ =CFO(CF ₂ CF(Y ¹⁵ )O) _m (CF ₂ ) _n F

(wherein Y ¹⁵ represents a fluorine atom or a trifluoromethyl group; m is an integer of 1 to 4; n is an integer of 1 to 4). At least one selected from the group consisting of fluoro monomers represented by .

Each component contained in the perfluoroelastomer composition of the present disclosure will be described in more detail.

(Perfluoroelastomer (A) containing nitrile group)

The perfluoroelastomer (A) contains a nitrile group (-CN group). The nitrile group-containing perfluoroelastomer (A) can be crosslinked by forming a triazine ring through cyclotrimerization of the nitrile group, and can impart excellent compression set properties and heat resistance to the crosslinked product.

The nitrile group-containing perfluoroelastomer (A) preferably has a nitrile group (-CN group) at the main chain terminal and/or side chain.

The nitrile group-containing perfluoroelastomer (A) preferably contains a monomer unit having a nitrile group. As a monomer having a nitrile group,

Formula: CX ⁴ ₂ =CX ⁵ R _f ² -CN

₍ ^In the formula, X ^{4 and} , a linear or branched alkylene group or oxyalkylene group in which part or all of the hydrogen atoms may be substituted with fluorine atoms).

As a monomer having a nitrile group, for example

Formula: CY ¹ ₂ =CY ¹ (CF ₂ ) _n -CN

(In the formula, Y ¹ is each independently a hydrogen atom or a fluorine atom, and n is an integer of 1 to 8.)

Formula: CF ₂ =CFCF ₂ Rf ⁸ -CN

(where Rf ⁸ is -(OCF ₂ ) _n - or -(OCF(CF ₃ )) _n -, and n is an integer of 0 to 5)

Formula: CF ₂ =CFCF ₂ (OCF(CF ₃ )CF ₂ ) _m (OCH ₂ CF ₂ CF ₂ ) _n OCH ₂ CF ₂ -CN

(In the formula, m is an integer from 0 to 5, and n is an integer from 0 to 5)

Formula: CF ₂ =CFCF ₂ (OCH ₂ CF ₂ CF ₂ ) _m (OCF(CF ₃ )CF ₂ ) _n OCF(CF ₃ )-CN

(In the formula, m is an integer from 0 to 5, and n is an integer from 0 to 5)

Formula: CF ₂ =CF(OCF ₂ CF(CF ₃ )) _m O(CF ₂ ) _n -CN

(Wherein, m is an integer from 0 to 5, and n is an integer from 1 to 8)

Formula: CF ₂ =CF(OCF ₂ CF(CF ₃ )) _m -CN

(where m is an integer from 1 to 5)

Formula: CF ₂ =CFOCF ₂ (CF(CF ₃ )OCF ₂ ) _n CF(-CN)CF ₃

(where n is an integer from 1 to 4)

Formula: CF ₂ =CFO(CF ₂ ) _n OCF(CF ₃ )-CN

(where n is an integer from 2 to 5)

Formula: CF ₂ =CFO(CF ₂ ) _n -(C ₆ H ₄ )-CN

(where n is an integer from 1 to 6)

Formula: CF ₂ =CF(OCF ₂ CF(CF ₃ )) _n OCF ₂ CF(CF ₃ )-CN

(where n is an integer from 1 to 2)

Formula: CH ₂ =CFCF ₂ O(CF(CF ₃ )CF ₂ O) _n CF(CF ₃ )-CN

(where n is an integer from 0 to 5)

Formula: CF ₂ =CFO(CF ₂ CF(CF ₃ )O) _m (CF ₂ ) _n -CN

(Wherein, m is an integer from 0 to 5, and n is an integer from 1 to 3)

Formula: CH ₂ =CFCF ₂ OCF(CF ₃ )OCF(CF ₃ )-CN

Formula: CH ₂ =CFCF ₂ OCH ₂ CF ₂ -CN

Formula: CF ₂ =CFO(CF ₂ CF(CF ₃ )O) _m CF ₂ CF(CF ₃ )-CN

(In the formula, m is an integer greater than or equal to 0)

Formula: CF ₂ =CFOCF(CF ₃ )CF ₂ O(CF ₂ ) _n -CN

(In the formula, n is an integer greater than or equal to 1)

Formula: CF ₂ =CFOCF ₂ OCF ₂ CF(CF ₃ )OCF ₂ -CN

Monomers represented by and the like can be mentioned, and these can be used individually or in arbitrary combinations.

As monomers having a nitrile group (-CN group), among them,

Formula: CF ₂ =CF(OCF ₂ CF(CF ₃ )) _m O(CF ₂ ) _n -CN

A monomer represented by (where m is an integer from 0 to 5 and n is an integer from 1 to 8) is preferable, and CF ₂ =CFOCF ₂ CF(CF ₃ )OCF ₂ CF ₂ CN is more preferable.

Examples of the nitrile group-containing perfluoroelastomer (A) include a copolymer of TFE/fluoromonomer represented by general formula (13), (14) or (15)/monomer having a nitrile group. In this case, the content of the monomer unit having a nitrile group is 0.1 with respect to the total amount of the TFE unit and the fluoromonomer unit represented by general formulas (13), (14) and (15) from the viewpoint of good crosslinking characteristics and heat resistance. The amount may be 5 mol% or 0.3 to 3 mol%.

When the nitrile group-containing perfluoroelastomer (A) is a TFE/perfluoro(methylvinyl ether) (PMVE)/monomer copolymer having a nitrile group, the composition (mol%) of the nitrile group-containing perfluoroelastomer (A) is , preferably 45 to 89.9/10 to 54.9/0.01 to 4, more preferably 55 to 77.9/20 to 49.9/0.1 to 3.5, and even more preferably 55 to 69.8/30 to 44.8/0.2 to 3. , most preferably 55.3 to 69.5/30.3 to 44.5/0.2 to 2.8.

If the nitrile group-containing perfluoroelastomer (A) is TFE/fluoromonomer having 4 to 12 carbon atoms represented by the general formula (13), (14) or (15)/monomer copolymer having a nitrile group, it contains a nitrile group. The composition (mol%) of the perfluoroelastomer (A) is preferably 50 to 89.9/10 to 49.9/0.01 to 4, more preferably 60 to 87.9/12 to 39.9/0.1 to 3.5, and even more preferably Preferably it is 65 to 84.8/15 to 34.8/0.2 to 3, and most preferably it is 66 to 84.3/15.5 to 33.8/0.2 to 2.8.

Outside these composition ranges, the properties as a rubber elastomer are lost and the properties tend to be similar to those of resin.

As the nitrile group-containing perfluoroelastomer (A), a monomer copolymer having a fluoromonomer/nitrile group represented by TFE/general formula (15), and a fluoromonomer/nitrile group represented by TFE/general formula (13). At least one type selected from the group consisting of monomer copolymers having

The nitrile group-containing perfluoroelastomer (A) may have a polar end group. Terminal group refers to any group present in the main chain or optionally long or short terminal of the polymer. Polar terminal groups include ionic groups such as carboxylate (-COO ^- ) and sulfonate (-OSO ₃ ^- ) groups, and alcohol (-CH ₂ OH), acyl fluoride (-COF), and amide (-CONH ₂ ), etc. include nonionic groups. Polar terminal groups can be introduced into the elastomer by using an inorganic peroxide or the like as a polymerization initiator when producing a perfluoroelastomer by polymerizing a monomer. The presence or absence of polar terminal groups can be confirmed by Fourier transform infrared spectroscopy (FTIR).

Since the nitrile group-containing perfluoroelastomer (A) has excellent compression set properties at high temperatures, the glass transition temperature is preferably -70°C or higher, more preferably -60°C or higher, and even more preferably -50°C or higher. desirable. Moreover, from the viewpoint of good cold resistance, the temperature is preferably 5°C or lower, more preferably 0°C or lower, and even more preferably -3°C or lower.

The glass transition temperature is obtained by obtaining a DSC curve by heating 10 mg of the sample at 10°C/min using a differential scanning calorimeter (DSC 822e, manufactured by Mettler Toledo), and is an extension of the base line before and after the secondary transition of the DSC curve. It can be obtained as the temperature representing the midpoint of the two intersection points of the tangent lines at the inflection point of the DSC curve.

Since the nitrile group-containing perfluoroelastomer (A) has good heat resistance, the Mooney viscosity ML(1+20) at 170°C is preferably 30 or more, more preferably 40 or more, and still more preferably 50 or more. Moreover, from the viewpoint of good processability, it is preferable that it is 150 or less, more preferably 120 or less, and even more preferably 110 or less.

The Mooney viscosity can be measured according to JIS K6300 at 170°C using a Mooney viscometer type MV2000E manufactured by ALPHA TECHNOLOGIES.

The nitrile group-containing perfluoroelastomer (A) can be produced by a conventional method.

(Iodine- or bromine-containing perfluoroelastomer (B) that does not contain nitrile groups)

The perfluoroelastomer (B) contains iodine atoms or bromine atoms. The perfluoroelastomer (B) does not contain nitrile groups and differs from the perfluoroelastomer (A) in this respect. It is presumed that the perfluoroelastomer (B) exists in the cross-linked product without being cross-linked even in the presence of the compound (C), and imparts excellent transparency to the cross-linked product without impairing the excellent compression set properties of the cross-linked product. Furthermore, the iodine- or bromine-containing perfluoroelastomer (B) does not volatilize by heating, continues to exist in the cross-linked product, and has excellent compatibility with the nitrile group-containing perfluoroelastomer (A), providing excellent compression set. It is assumed that deformation characteristics and excellent transparency can be imparted to the cross-linked product. Moreover, since the iodine- or bromine-containing perfluoroelastomer (B) can be produced by the iodine transfer polymerization method, the molecular weight can be easily adjusted. Therefore, in that the elastomer (B) having an appropriate molecular weight according to the physical properties of the nitrile group-containing perfluoroelastomer (A) can be easily manufactured, the use of the elastomer (B) results in compression set of the cross-linked product. It is also advantageous in that the characteristics can be maintained and transparency can be easily improved.

The iodine- or bromine-containing perfluoroelastomer (B) preferably has iodine atoms or bromine atoms at the main chain terminal and/or side chain.

The iodine- or bromine-containing perfluoroelastomer (B) includes a perfluoroelastomer containing a monomer unit having an iodine atom or a bromine atom, a perfluoroelastomer having an iodine atom or a bromine atom at the main chain end, and an iodine atom at the main chain end. At least one type selected from the group consisting of perfluoroelastomers containing a monomer unit having an atom or a bromine atom and further containing a monomer unit having an iodine atom or a bromine atom is preferred.

As a monomer having an iodine atom or a bromine atom,

Formula: CX ⁴ ₂ =CX ⁵ R _f ² -X

₍ ^In the formula, X ^{4 and} , a linear or branched alkylene group or oxyalkylene group in which part or all of the hydrogen atoms may be substituted with fluorine atoms, and X is an iodine atom or a bromine atom.

As a monomer having an iodine atom or a bromine atom, for example

Formula: CX ¹⁶ ₂ =CX ¹⁶ -Rf ¹⁶ CHR ¹⁶

₍ ^{Wherein ,} ) oxyalkylene group, R ¹⁶ is a hydrogen atom or CH ₃ , X is an iodine atom or a bromine atom) fluoro monomer represented by

Formula: CX ¹⁶ ₂ =CX ¹⁶ -Rf ¹⁷

^{( Wherein} _, ) a fluoro monomer represented by an oxyalkylene group,

Formula: CF ₂ =CFO(CF ₂ CF(CF ₃ )O) _m (CF ₂ ) _n -X

(wherein m is an integer from 0 to 5, n is an integer from 1 to 3, and X is an iodine atom, a bromine atom, or -CH ₂ I),

Formula: CH ₂ =CFCF ₂ O(CF(CF ₃ )CF ₂ O) _m (CF(CF ₃ )) _n -X

(wherein m is an integer from 0 to 5, n is an integer from 1 to 3, and You can.

X ¹⁶ is preferably a fluorine atom. Rf ¹⁶ and Rf ¹⁷ are preferably perfluoroalkylene groups having 1 to 5 carbon atoms. R ¹⁶ is preferably a hydrogen atom.

As a monomer having an iodine atom or a bromine atom, CF ₂ =CFOCF ₂ CF(CF ₃ )OCF ₂ CF ₂ CH ₂ I, CF ₂ =CFOCF ₂ CF ₂ CH ₂ I, and CH ₂ =CHCF ₂ CF ₂ I. At least one type selected from the group is preferable, and CF ₂ =CFOCF ₂ CF ₂ CH ₂ I is more preferable.

A perfluoroelastomer having an iodine atom or a bromine atom at the main chain terminal can be produced by using an iodine compound or a bromine compound as a chain transfer agent when producing the perfluoroelastomer by polymerizing monomers. Examples of polymerization methods using an iodine compound or a bromine compound include, for example, a method of performing emulsion polymerization in an aqueous medium under pressure in the presence of an iodine compound or a bromine compound in a substantially oxygen-free state (iodine transfer polymerization law). Representative examples of the iodine compound or bromine compound to be used include, for example, the general formula:

(In the formula, x and y are each integers of 0 to 2 and satisfy 1≤x+y≤2, and R ²¹ is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon having 1 to 16 carbon atoms. group, or a hydrocarbon group having 1 to 3 carbon atoms and may include an oxygen atom).

Iodine compounds and bromine compounds include, for example, 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, and 1,4. -Diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane , 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n- Propane, CF ₂ Br ₂ , BrCF ₂ CF ₂ Br, CF ₃ CFBrCF ₂ Br, CFClBr ₂ , BrCF ₂ CFClBr, CFBrClCFClBr, BrCF ₂ CF ₂ CF ₂ Br, BrCF ₂ CFBrOCF ₃ , 1-bromo-2-iodo Perfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bro mo-4-iodoperfluorobutene-1,2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo substituent of benzene, diiodomonobromo substituent, and (2-iodoperfluorobutene) doethyl) and (2-bromoethyl) substituents, etc., and these compounds may be used individually or in combination with each other.

Among these, in terms of polymerization reactivity, crosslinking reactivity, ease of availability, etc., 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane are used. It is desirable.

The content of iodine atoms and bromine atoms in the iodine or bromine-containing perfluoroelastomer (B) is preferably 0.001 to 10% by mass, more preferably 0.01% by mass or more, and still more preferably 0.1% by mass or more. , more preferably 5% by mass or less. If the content of iodine atoms and bromine atoms is too small, the haze value increases, and there is a risk that a cross-linked product showing excellent transparency may not be obtained. The content of iodine atoms and bromine atoms can be measured by elemental analysis.

As the iodine- or bromine-containing perfluoroelastomer (B), the iodine- or bromine-containing perfluoroelastomer (B) comprising TFE units, for example, represented by TFE/general formula (13), (14) or (15) at least one selected from the group consisting of a fluoromonomer copolymer and TFE/fluoromonomer represented by general formula (13), (14) or (15)/monomer copolymer having an iodine atom or a bromine atom. do.

When the iodine- or bromine-containing perfluoroelastomer (B) is a TFE/perfluoro(methylvinyl ether) (PMVE) copolymer, the composition (mol%) of the iodine- or bromine-containing perfluoroelastomer (B) is preferably is 45 to 90/10 to 55, more preferably 55 to 80/20 to 45, further preferably 55 to 70/30 to 45, and most preferably 56 to 69.5/30.5 to 44.

When the iodine- or bromine-containing perfluoroelastomer (B) is a TFE/PMVE/monomer copolymer having iodine atoms or bromine atoms, the composition (mol%) of the iodine- or bromine-containing perfluoroelastomer (B) is preferably 45 to 89.9/10 to 54.9/0.01 to 4, more preferably 55 to 77.9/20 to 49.9/0.01 to 3.5, further preferably 55 to 69.8/30 to 44.8/0.03 to 3.0, and most preferably is 55.3 to 69.5/30.3 to 44.5/0.05 to 2.5.

When the iodine- or bromine-containing perfluoroelastomer (B) is a TFE/fluoro monomer copolymer having 4 to 12 carbon atoms represented by the general formula (13), (14) or (15), the iodine- or bromine-containing perfluoroelastomer The composition (mol%) of the elastomer (B) is preferably 50 to 90/10 to 50, more preferably 60 to 88/12 to 40, and even more preferably 65 to 85/15 to 35, Most preferably it is 66 to 84/16 to 34.

The iodine- or bromine-containing perfluoroelastomer (B) is a TFE/fluoromonomer having 4 to 12 carbon atoms represented by the general formula (13), (14) or (15)/monomer copolymer having an iodine atom or a bromine atom. In this case, the composition (mol%) of the iodine- or bromine-containing perfluoroelastomer (B) is preferably 50 to 89.9/10 to 49.9/0.01 to 4, more preferably 60 to 87.9/12 to 39.9/0.1. to 3.5, more preferably 65 to 84.8/15 to 34.8/0.2 to 3.0, and most preferably 66 to 84.3/15.5 to 33.8/0.2 to 2.0.

Outside these composition ranges, the properties as a rubber elastomer are lost and the properties tend to be similar to those of resin.

The iodine- or bromine-containing perfluoroelastomer (B) includes TFE/fluoromonomer copolymer represented by formula (13), TFE/fluoromonomer represented by formula (13)/having an iodine atom or a bromine atom. Monomer copolymer, TFE/fluoro monomer copolymer represented by formula (15), and TFE/fluoro monomer represented by formula (15)/monomer copolymer having iodine atom or bromine atom. At least one type is preferred.

Since the iodine- or bromine-containing perfluoroelastomer (B) has excellent compression set properties at high temperatures, the glass transition temperature is preferably -70°C or higher, more preferably -60°C or higher, and -50°C or higher. It is more desirable. Moreover, from the viewpoint of good cold resistance, the temperature is preferably 5°C or lower, more preferably 0°C or lower, and even more preferably -3°C or lower.

The glass transition temperature is obtained by obtaining a DSC curve by heating 10 mg of the sample at 10°C/min using a differential scanning calorimeter (DSC 822e, manufactured by Mettler Toledo), and is an extension of the base line before and after the secondary transition of the DSC curve. It can be obtained as the temperature representing the midpoint of the two intersection points of the tangent lines at the inflection point of the DSC curve.

Since the iodine- or bromine-containing perfluoroelastomer (B) has good heat resistance, the Mooney viscosity ML(1+10) at 100°C is preferably 10 or more, more preferably 20 or more, and still more preferably 25 or more. . Moreover, from the viewpoint of good processability, it is preferable that it is 120 or less, more preferably 100 or less, and even more preferably 80 or less.

The Mooney viscosity can be measured according to JIS K6300 at 100°C using a Mooney viscometer type MV2000E manufactured by ALPHA TECHNOLOGIES.

Perfluoroelastomer (B) can be produced by a conventional method.

The content of the iodine or bromine-containing perfluoroelastomer (B) is preferably 0.5 to 10 parts by mass, more preferably 1.0 parts by mass or more, based on 100 parts by mass of the nitrile group-containing perfluoroelastomer (A). , more preferably 2.0 parts by mass or more, especially preferably 3.0 parts by mass or more, more preferably 7 parts by mass or less, and even more preferably 5 parts by mass or less. If the content of the iodine or bromine-containing perfluoroelastomer (B) is too high, there is a risk that a cross-linked product showing excellent compression set properties may not be obtained, and crushing (cracks) may occur during compression. If the content of the iodine or bromine-containing perfluoroelastomer (B) is too small, the haze value will increase, and there is a risk that a cross-linked product showing excellent transparency may not be obtained.

(Compound (C))

The perfluoroelastomer composition of the present disclosure contains at least one compound (C) selected from the group consisting of inorganic nitrides and ammonia-generating compounds. By containing the compound (C), the nitrile group of the nitrile group-containing perfluoroelastomer (A) is cyclized and trimerized to form a triazine ring, and the nitrile group-containing perfluoroelastomer (A) can be crosslinked. On the other hand, the iodine- or bromine-containing perfluoroelastomer (B), which does not contain a nitrile group, is not crosslinked even in the presence of the compound (C), and exists in an uncrosslinked state in the obtained crosslinked product. It is presumed that the iodine- or bromine-containing perfluoroelastomer (B), which exists in an uncrosslinked state in the obtained cross-linked product, imparts excellent transparency to the cross-linked product without impairing the excellent compression set characteristics of the cross-linked product.

The inorganic nitride is not particularly limited, but includes silicon nitride (Si ₃ N ₄ ), lithium nitride, titanium nitride, aluminum nitride, boron nitride, vanadium nitride, and zirconium nitride. Among these, silicon nitride is preferable because nano-sized fine particles can be supplied.

As a compound that generates ammonia, a compound that generates ammonia at 40 to 330°C is preferable.

As the ammonia-generating compound, urea or a derivative thereof and an ammonium salt are preferable, urea or an ammonium salt is more preferable, and urea is still more preferable. The ammonium salt may be an organic ammonium salt or an inorganic ammonium salt. Additionally, the ammonia-generating compound may be one that reacts with a trace amount of water to generate ammonia.

Derivatives of urea include biurea, thiourea, urea hydrochloride, and biuret.

Examples of organic ammonium salts include ammonium salts of non-fluorinated carboxylic acids or sulfonic acids, such as ammonium benzoate, ammonium adipate, and ammonium phthalate.

Examples of the inorganic ammonium salt include compounds described in Japanese Patent Application Laid-Open No. 9-111081, such as ammonium sulfate, ammonium carbonate, ammonium nitrate, and ammonium phosphate.

Additionally, ammonia-generating compounds include acetaldehyde ammonia, hexamethylenetetramine, formamidine, formamidine hydrochloride, formamidine acetate, t-butylcarbamate, benzylcarbamate, and phthalamide.

The compound (C) is preferably at least one selected from the group consisting of urea, a derivative of urea, and inorganic nitride, and inorganic nitride is more preferable because it can achieve both excellent compression set properties and excellent transparency at a high level. And silicon nitride is more preferable.

The content of compound (C) is preferably 0.05 to 10 parts by mass, more preferably 0.1 parts by mass or more, and even more preferably 0.2 parts by mass, based on 100 parts by mass of the nitrile group-containing perfluoroelastomer (A). parts by mass or more, more preferably 5 parts by mass or less, further preferably 3 parts by mass or less, particularly preferably 1.0 parts by mass or less, and most preferably 0.5 parts by mass or less. If the content of compound (C) is too high, scorching may occur, and if the content of compound (C) is too small, crosslinking of the nitrile group-containing perfluoroelastomer (A) becomes insufficient, resulting in excellent compression set properties. There is a risk that the cross-linked product shown may not be obtained.

(Other ingredients)

The perfluoroelastomer composition may further contain filler. In one embodiment of the perfluoroelastomer composition, from the viewpoint of further improving the transparency of the resulting cross-linked product, the filler is substantially not contained, for example, 0.01 parts by mass per 100 parts by mass of the nitrile group-containing perfluoroelastomer (A). Contains only less than one part by mass of filler.

As fillers, imide-based fillers with an imide structure such as polyimide, polyamidoimide, and polyetherimide, polyarylate, polysulfone, polyether sulfone, polyphenylene sulfide, polyether ether ketone, polyether ketone, poly Organic fillers made of engineering plastics such as oxybenzoate, metal oxide fillers such as silicon oxide, aluminum oxide, and yttrium oxide, metal carbides such as silicon carbide and aluminum carbide, metal nitride fillers such as aluminum nitride, carbon black, carbon fluoride, etc. of inorganic fillers.

Among these, carbon black, aluminum oxide, silicon oxide, yttrium oxide, silicon carbide, polyimide, and carbon fluoride are preferable in terms of their effectiveness in shielding various plasmas.

Additionally, the above-mentioned fillers may be blended individually or in combination of two or more types.

Especially in fields where high purity and non-contamination are not required, common additives such as processing aids, plasticizers, colorants, etc. can be added to the composition as needed, and commercial crosslinking agents or crosslinking aids other than those mentioned above can be used. One or more types may be combined.

The composition may contain an organic basic compound. Examples of organic basic compounds include octadecylamine of the formula: CH ₃ (CH ₂ ) ₁₇ -NH ₂ ;

Formula: H ₂ NC(O)-(CH ₂ ) ₁₁ -CH=CH-(CH ₂ ) ₇ Erucamide of CH ₃ ;

Formula: Oleamide of H ₂ NC(O)-(CH ₂ ) ₇ -CH=CH-(CH ₂ ) ₇ CH ₃ ;

Formula: H ₂ N-(CH ₂ ) ₆ -NH ₂ of hexamethylenediamine

ceremony:

1,8-diazabicycloundeca-7-ene (DBU), etc.

The perfluoroelastomer composition can be prepared by mixing each of the above components using a typical polymer processing machine, such as an open roll, Banbury mixer, or kneader. In addition, it can also be prepared by using a closed mixer. The perfluoroelastomer composition can be suitably used as a molding material for obtaining a cross-linked product by cross-linking molding.

(Cross-linked product)

By crosslinking the perfluoroelastomer composition, a crosslinked perfluoroelastomer product can be obtained. The cross-linked perfluoroelastomer of the present disclosure has excellent compression set properties and excellent transparency.

The crosslinked perfluoroelastomer according to one embodiment has a haze value of 95% or less and a compression set of 25 to 40%. The cross-linked perfluoroelastomer according to this embodiment exhibits excellent compression set properties even at high temperatures and also exhibits excellent transparency, so it can be used as a sealant used in fields that require excellent heat resistance and high cleanliness. there is. The crosslinked perfluoroelastomer according to this embodiment is suitably obtained by crosslinking the perfluoroelastomer composition of the present disclosure.

The haze value of the perfluoroelastomer crosslinked product is preferably 95% or less, more preferably 90% or less, and still more preferably 80% or less. The lower the haze value of the cross-linked perfluoroelastomer, the more preferable it is, but the lower limit of the haze value may be, for example, 50% or more. The haze value can be measured based on ASTM D1003 for cross-linked products of arbitrary thickness.

The compression set of the cross-linked perfluoroelastomer is preferably 50% or less, more preferably 40% or less, and still more preferably 30% or less.

The compression set of the perfluoroelastomer crosslinked product is measured by leaving it at 300°C for 72 hours at a compression rate of 25%. The compression set is calculated by compressing the cross-linked product to a compression ratio of 25%, leaving it at 300°C for 72 hours, releasing the compression, leaving it at 23°C for 30 minutes, and measuring the thickness of the cross-linked product before and after compression. You can.

The total light transmittance of the perfluoroelastomer crosslinked product is preferably 85% or more, more preferably 88% or more, and still more preferably 90% or more. The higher the total light transmittance of the cross-linked perfluoroelastomer, the more preferable it is, but the upper limit of the total light transmittance may be, for example, 95% or less. The total light transmittance can be measured based on ASTM D1003 for cross-linked products of arbitrary thickness.

The perfluoroelastomer crosslinked product preferably contains a triazine ring. The triazine ring does not impair the transparency of the cross-linked product and provides excellent compression set properties at high temperatures to the cross-linked product. The presence or absence of a triazine ring in the perfluoroelastomer crosslinked product can be confirmed by Fourier transform infrared spectroscopy (FT-IR).

The content of the triazine ring in the perfluoroelastomer crosslinked product is preferably 0.04 or more, and more preferably 0.05 or more. In the present disclosure, the content of the triazine ring in the cross-linked perfluoroelastomer is expressed by the ratio of the content of the triazine ring to the content of CF bonds in the cross-linked perfluoroelastomer. The content of the triazine ring in the perfluoroelastomer crosslinked product can be measured by Fourier transform infrared spectroscopy (FT-IR). The infrared spectrum of the cross-linked product was acquired using a Fourier transform infrared spectrophotometer (FT-IR), and the absorbance of the triazine ring peak (1555 cm ^-1 ) relative to the overtone vibration peak (2360 cm ^-1 ) of the CF bond shown in the infrared spectrum was measured. By calculating the ratio (A1555/A2360), the content of the triazine ring can be determined.

The perfluoroelastomer crosslinked product preferably contains iodine atoms or bromine atoms. The iodine atom or bromine atom provides excellent transparency to the cross-linked product without impairing the compression set properties of the cross-linked product. The presence or absence of iodine atoms or bromine atoms in the perfluoroelastomer cross-linked product can be confirmed by elemental analysis using an ion chromatograph of the incinerated product obtained by incinerating the cross-linked product.

The content of iodine atoms and bromine atoms in the cross-linked perfluoroelastomer is preferably 0.0001 mass% or more, more preferably 0.0005 mass% or more, further preferably 0.0008 or more, and preferably 0.010 mass% or less. , more preferably 0.005 or less, and still more preferably 0.002 mass% or less. The content of iodine atoms and bromine atoms can be measured by elemental analysis using an ion chromatograph of the incinerated product obtained by incinerating the cross-linked product.

The perfluoroelastomer crosslinked product preferably contains silicon atoms. Silicon atoms impart both excellent compression set properties and excellent transparency to the crosslinked product at a high level. The presence or absence of silicon atoms in the perfluoroelastomer crosslinked product can be confirmed by energy dispersive X-ray analysis (EDX).

The content of silicon atoms in the perfluoroelastomer crosslinked product is preferably 0.05 mass% or more, more preferably 0.1 mass% or more, preferably 1.0 mass% or less, and even more preferably 0.5 mass% or less. . The content of silicon atoms can be measured by energy dispersive X-ray analysis (EDX).

A method of obtaining a perfluoroelastomer crosslinked product from a perfluoroelastomer composition includes obtaining a preform by molding the perfluoroelastomer composition as a molding material, and then crosslinking the preform. The method of obtaining a preform from the perfluoroelastomer composition may be a conventional method, or may be performed by known methods such as heating and compressing with a mold, press-fitting into a heated mold, or extruding with an extruder. In the case of extruded products such as hoses and wires, a perfluoroelastomer crosslinked product can be obtained by heat crosslinking using steam or the like after extrusion.

The crosslinking can be performed in the order of primary crosslinking and secondary crosslinking. Primary crosslinking is preferably performed at 150 to 250°C for 5 to 120 minutes, and is more preferably performed at 170 to 200°C for 5 to 60 minutes. As the crosslinking means, a known crosslinking means may be used, and examples include press crosslinking and the like.

Secondary crosslinking is preferably performed at 180 to 320°C for 2 to 48 hours, and is more preferably performed at 200 to 310°C for 5 to 24 hours. Additionally, you may have a temperature change within this temperature range. As a crosslinking means, a known crosslinking means may be used, and examples include oven crosslinking and the like.

The cross-linked perfluoroelastomer of the present disclosure can be suitably used as a sealant in semiconductor manufacturing equipment that requires heat resistance, particularly semiconductor manufacturing equipment that is subjected to high-density plasma irradiation. Examples of the sealing material include O-rings, square rings, gaskets, packings, oil seals, bearing seals, and lip seals.

In addition, it can also be used as various polymer products used in semiconductor manufacturing equipment, such as diaphragms, tubes, hoses, various rubber rolls, and belts. It can also be used as a coating material or lining material.

In addition, the semiconductor manufacturing equipment referred to in this disclosure is not limited to equipment for manufacturing semiconductors in particular, and is widely used in the semiconductor field that requires a high level of cleanliness, such as equipment for manufacturing liquid crystal panels and plasma panels. It includes the entire manufacturing equipment that is used, and examples include the following.

(1) Etching device

dry etching device

plasma etching device

reactive ion etching device

Reactive ion beam etching device

sputter etching device

Ion beam etching device

wet etching device

ashing device

(2) Cleaning device

Dry etching cleaning device

UV/O ₃ cleaning device

Ion beam cleaning device

laser beam cleaning device

plasma cleaning device

gas etching cleaning device

extraction cleaning device

Soxhlet extraction cleaning device

High temperature high pressure extraction cleaning device

Microwave extraction cleaning device

Supercritical extraction cleaning device

(3) Exposure device

stepper

Coater/Developer

(4) Polishing device

CMP device

(5) Tabernacle equipment

CVD device

sputtering device

(6) Diffusion/ion implantation device

oxidation diffusion device

ion implantation device

The crosslinked perfluoroelastomer of the present disclosure exhibits excellent performance as a sealant for, for example, a CVD device, a plasma etching device, a reactive ion etching device, an ashing device, or an excimer laser exposure device.

Although the embodiment has been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

Example

Next, embodiments of the present disclosure will be described using examples, but the present disclosure is not limited to these examples.

Each numerical value in the examples was measured by the following method.

(Composition of perfluoroelastomer)

¹⁹ Obtained by F-NMR analysis.

(Iodine atom content of perfluoroelastomer)

Put 20 ml of pure water in a quartz flask, add 30 mg of 12 mg of perfluoroelastomer mixed with Na ₂ CO ₃ and K ₂ CO ₃ in a 1:1 (weight ratio) to the platinum basket, and place in the quartz flask, After burning in oxygen and leaving for 30 minutes, 5 mg of Na ₂ SO ₃ was added and shaken, the generated combustion gas was dissolved in the liquid in a quartz flask, and the concentration of iodine ions in the resulting solution was measured using a Shimadzu 20A ion chromatograph. It was measured. The iodine content of the perfluoroelastomer was determined using a calibration curve prepared using a KI standard solution containing 0.5 ppm of iodine ions and a KI standard solution containing 1.0 ppm.

(Mooney viscosity of perfluoroelastomer)

Measurement was performed according to JIS K6300 at 170°C or 100°C using a Mooney viscometer MV2000E manufactured by ALPHA TECHNOLOGIES.

(Content of triazine ring in cross-linked product)

The infrared spectrum of the cross-linked product was acquired using a Fourier transform infrared spectrophotometer (FT-IR), and the absorbance of the triazine ring peak (1555 cm ^-1 ) relative to the overtone vibration peak (2360 cm ^-1 ) of the CF bond shown in the infrared spectrum was measured. The ratio (A1555/A2360) was calculated, and the calculated absorbance ratio was used as the content of the triazine ring in the cross-linked product.

(Content of iodine atoms in cross-linked product)

The cross-linked product was subjected to incineration treatment and the obtained incineration was measured by elemental analysis using an ion chromatograph.

(Content of silicon atoms in cross-linked product)

The content of silicon atoms in the cross-linked product was calculated from the composition of the composition used to prepare the cross-linked product. Additionally, the presence or absence and content of silicon atoms in the cross-linked product can also be measured by energy dispersive X-ray analysis (EDX) of the cross-linked product. In Table 1, cases where silicon atoms in the cross-linked product could be detected by EDX were described as “present”, and cases where silicon atoms in the cross-linked product could not be detected were described as “none.”

(Total light transmittance, haze value)

Using a cross-linked product with a thickness of 2 mm, it was measured using Haze Guard II (product name) (manufactured by Toyo Seki Seisakusho) in accordance with ASTM D1003.

(compression set)

Compression set was measured according to the method described in ASTM D395 or JIS K6262. The O-rings produced in the examples and comparative examples were compressed to a compression ratio of 25% at room temperature using a compression device (an O-ring with a thickness (wire diameter) of 3.5 mm was compressed to a thickness of 2.625 mm).

Next, the compression device to which the compressed O-ring was fixed was placed in an electric furnace and left at 300°C for 72 hours, and then the compression device was taken out from the electric furnace. The O-ring was removed from the compression device, the separated O-ring was placed in a constant temperature room, left at 23°C for 30 minutes, and the thickness (t ₂ ) of the O-ring was measured. The compression set was obtained using the following equation.

Compression set rate (%)=(t ₀ -t ₂ )/(t ₀ -t ₁ )×100

t ₀ : Original thickness of O-ring (mm)

t ₁ : Thickness of spacer (mm)

t ₂ : Thickness of O-ring after compression test (mm)

In the above test, t ₀ =3.5 mm and t ₁ =2.625 mm.

(state physical properties)

Using a cross-linked product with a thickness of 2 mm, tensile strength at break (MPa), 100% modulus (MPa), and elongation at break (%) were measured according to JIS-K6251.

(ShoreA Peak)

Using a cross-linked product with a thickness of 2 mm, hardness (ShoreA) was measured according to JIS-K6253 (peak value).

In the examples and comparative examples, the following materials were used.

<Perfluoroelastomer containing nitrile group (A)>

Elastomer (a1)

Composition: TFE/PMVE/CF ₂ =CFOCF ₂ CF(CF ₃ )OCF ₂ CF ₂ CN=59.4/40.1/0.5 (mol%)

Mooney viscosity (ML1+20(170℃)): 80

It has a polar terminal group (carboxylate group).

<Iodine- or bromine-containing perfluoroelastomer (B) that does not contain a nitrile group>

Elastomer (b1)

Composition: TFE/PMVE/CF ₂ =CFOCF ₂ CF ₂ CH ₂ I=66.7/33.2/0.1 (mol%)

Mooney viscosity (ML1+10(100℃)): 65

Iodine atom content: 0.40wt%

Elastomer (b2)

Composition: TFE/CF ₂ =CF(OCF ₂ CF(CF ₃ ) ₂ OCF ₂ CF ₂ CF ₃ /CF ₂ =CFOCF ₂ CF ₂ CH ₂ I=79.6/20.0/0.4 (mol%)

Mooney viscosity (ML1+10(100℃)): 27

Iodine atom content: 0.20wt%

Elastomer (b3)

Composition: TFE/PMVE=62/38 (mol%)

Mooney viscosity (ML1+10 (100℃)): 50

Iodine atom content: 0.24wt%

<Compound (C)>

Compound (c1): Silicon nitride (Si ₃ N ₄ )

Compound (c2): Burette

Compound (c3): Urea

Comparative Example 1

To the elastomer (a1), 0.25 phr of silicon nitride (Si ₃ N ₄ ) (SN-A00 manufactured by Ube Kosan Corporation) was added and kneaded with an open roll to prepare a crosslinkable fluororubber composition. The obtained fluororubber composition was crosslinked by pressing at 180°C for 20 minutes, and then oven crosslinked at 200 to 290°C for 18 hours to produce a crosslinked product with a thickness of 2 mm and an O-ring (AS-568A-214). (size) molded products were produced. Using the obtained molded article, the total light transmittance, haze value, compression set, and state physical properties were measured according to the method shown above. The results are shown in Table 1.

Comparative Example 2

A fluororubber composition and molded article were produced in the same manner as in Comparative Example 1, except that a burette (manufactured by Kanto Chemical Co., Ltd.) was used instead of silicon nitride, and various evaluations were performed.

Comparative Example 3

A fluororubber composition and molded article were produced in the same manner as in Comparative Example 1, except that urea (manufactured by Kanto Chemical Co., Ltd.) was used instead of silicon nitride, and various evaluations were performed.

Examples 1 to 4

According to the composition shown in Table 1, silicon nitride (SN-A00 manufactured by Ube Kosan Co., Ltd.) and elastomer (b1) were added to elastomer (a1), and kneaded with an open roll to prepare a crosslinkable fluororubber composition. The obtained fluororubber composition was crosslinked by pressing at 180°C for 20 minutes, and then oven crosslinked at 200 to 290°C for 18 hours to produce a crosslinked product with a thickness of 2 mm and an O-ring (AS-568A- A molded product of size 214 was produced. Using the obtained molded article, the total light transmittance, haze value, compression set, and state physical properties were measured according to the method shown above.

Example 5

A fluororubber composition and a molded article were produced in the same manner as in Example 3, except that elastomer (b2) was used instead of elastomer (b1), and various evaluations were performed.

Example 6

A fluororubber composition and a molded article were produced in the same manner as in Example 3, except that elastomer (b3) was used instead of elastomer (b1), and various evaluations were performed.

The above results are shown in Table 1.

Claims (9)

Perfluoroelastomer containing nitrile group (A),
An iodine- or bromine-containing perfluoroelastomer (B) that does not contain a nitrile group, and
At least one compound (C) selected from the group consisting of inorganic nitrides and ammonia-generating compounds
A perfluoroelastomer composition containing. According to paragraph 1,
A perfluoroelastomer composition in which the content of the iodine- or bromine-containing perfluoroelastomer (B) is 0.5 to 10 parts by mass based on 100 parts by mass of the nitrile group-containing perfluoroelastomer (A). According to claim 1 or 2,
A perfluoroelastomer composition wherein the compound (C) is silicon nitride. A crosslinked perfluoroelastomer obtained by crosslinking the perfluoroelastomer composition according to any one of claims 1 to 3. A cross-linked perfluoroelastomer having a haze value of 95% or less and a compression set of 25 to 40%. According to clause 5,
A perfluoroelastomer crosslinked product with a total light transmittance of 85% or more. According to claim 5 or 6,
A cross-linked perfluoroelastomer containing a triazine ring. According to any one of claims 5 to 7,
A cross-linked perfluoroelastomer containing iodine atoms or bromine atoms. According to any one of claims 5 to 8,
A cross-linked perfluoroelastomer containing silicon atoms.